API MPMS 2.2D:2003 pdf free download.Manual of Petroleum Measurement Standards Chapter 2—Tank Calibration Section 2D—Calibration of Upright Cylindrical Tanks Using the Internal Electro- optical Distance Ranging Method
5 Equipment
5.1 ELECTRO-OPTICAL DISTANCE-RANGING INSTRUMENT
5.1.1 The angular measuring part of the instrument shall have an angular graduation and resolution equal to or better than ± 0.0002 gon*, a repeatability equal to or better than ± 0.0005 gon, and an uncertainty equal to or better than ± 0.001 gon. 2 .
5.1.2 The distance-measuring part of the instrument, used for direct determination of the distances, shall have a gradua- tion and resolution equal to or better than ± 1 mm, a repeat- ability equal to or better than ± 2 mm, and an uncertainty equal to or better than ± 2 mm.
5.2 INSTRUMENT MOUNTING consisting of a tripod which is Þrm and stable. The legs of the tripod shall be held Þrm, and steadied by suitable devices such as magnetic bearers.
5.3 LASER BEAM EMITTER having a low-power laser beam complying with IEC 825, which is either an integral part of the EODR instrument or a separate device. If the laser beam emitter is a separate device, it may be Þtted with a Þber optic light transmitter system and a theodolite telescope eye- piece connection, by which the laser beam may be transmit- ted through a theodolite, or such that it may be Þtted to a theodolite with its axis parallel to the axis of the theodolite. The laser beam may be coincident with the optical axis of the telescope Note 1: The laser beam emitter is used to position target points on the tank shell.
5.4 STADIA a rigid bar, usually 2 m long, such that the graduated length between the two stadia marks remains con- stant to within ± 0.02 mm.
5.5 EQUIPMENT FOR BOTTOM CALIBRATION (see 11.1) 5.6 AUXILIARY EQUIPMENT including: a. heavy weights to be set around the instrument to steady the unit; b. lighting within the tank, if required. 6 General Considerations
6.1 The EODR instrument shall be maintained so that the values of its measurement uncertainty do not exceed the val- ues given in this part of Chapter 2.
6.2 Tanks shall only be calibrated after they have been Þlled at least once with a liquid of density equal to or greater than that of the liquid which they will hold when in use. Note 2: The hydrostatic test applied to new tanks will satisfy this requirement in most cases.
6.3 Calibration shall be carried out without interruption.
6.4 The EODR instrument shall be veriÞed prior to calibration. The accuracy of the distance-measuring unit as well as the angular measuring unit shall be veriÞed using the procedures recommended by the manufacturer. The appropriate procedures given in Appendix A shall be used for the veriÞcation of equipment in the Þeld.
6.5 The tank shall be free from vibration and airborne dust particles.
Note 3: The ßoor of the tanks should be as free as possible from debris, dust and loose scale. 6.6 Lighting, when required, shall be placed within the tank so as not to interfere with the operation of the EODR instrument. 7 EODR Instrument Setup Within the Tank
7.1 INSTRUMENT SETUP
7.1.1 The instrument shall be set up with care, according to the procedure and instructions given by the manufacturers.
7.1.2 The instrument shall be set up so as to be stable. If necessary, the tank bottom in the vicinity of the instru- ment shall be made Þrm and steady by placing heavy weights in the area. The legs of the tripod on which the instrument is mounted shall be steadied by use of suitable devices, such as magnetic bearers, to prevent slippage on the tank bottom.
7.1.3 The instrument shall be located at, or near, the center of the tank. Note 4: This will ensure that the measured slope distances, at any one horizontal level, do not vary signiÞcantly and minimizes the overall uncertainty of slope distance determination.
7.1.4 The instrument shall be set horizontal, thus ensuring that the vertical axis (standing axis) is vertical.
7.1.5 The instrument shall be free from external vibration.
7.1.6 The sighting lines from the instrument to the tank shell wall shall not be obstructed.
7.2 PRELIMINARY PROCEDURES
7.2.1 Switch on the instrument and bring to operating temperature, allowing at least the minimum warmup time recommended by the manufacturer.API MPMS 2.2D pdf download.API MPMS 2.2D:2003 pdf free download
